(a) Field
Exemplary embodiments of the invention relate to a display device including a touch sensor.
(b) Description of the Related Art
A flat panel display, such as a liquid crystal display (“LCD”), an organic light emitting diode display (“OLED”) display, and an electrophoretic display, typically includes field generating electrodes and electro-optical active layers. The liquid crystal display includes a liquid crystal layer as the electro-optical active layer, the organic light emitting diode display includes an organic emission layer as the electro-optical active layer, and the electrophoretic display may include charged particles. The field generating electrode is connected to a switching element such as a thin film transistor thereby receiving a data signal, and the electro-optical active layer changes the data signal into the optical signal, thereby displaying the image.
Recently, a display device including a touch sensing function for an interaction with a user has been widely used. The touch sensing function determines whether an object, e.g., a finger of a user or a touch pen, touches a screen and touch position information thereof, by sensing a change of pressure or light on a screen in the display device when the user contacts the object to the screen to write a character or to draw a picture. The display device may receive an image signal based on the contact information.
This touch sensing function may be realized through a sensor. The sensor may be classified into various types such as a resistive type, a capacitive type, an electro-magnetic (“EM”) type and an optical type.
Among them, the capacitive type of sensor includes a sensing capacitor including a sensing electrode that transmits a sensing signal, thereby sensing a change of capacitance of the sensing capacitor generated when a conductor, such as a finger of a use, is close to the sensor to determine the contact and the contact position.
In the display device including a capacitive type touch sensing function, the aperture ratio and transmittance of the display device may be decreased by an additional circuit constitution.